The Tech Report spoke to NVIDIA's Tom Petersen about the free sync demo that AMD showed off yesterday. Petersen says he's excited to see a competitor take an interest in this but he claims that as things now stand, it's nearly impossible to implement free sync on a desktop display due to the use of different display architectures than on laptops. NVIDIA therefore introduced its own G-Sync logic chip but perhaps AMD will be able to convince existing scaler ASIC makers and monitor makers to add support for free sync as consumer interest picks up.
However, Petersen quickly pointed out an important detail about AMD's "free sync" demo: it was conducted on laptop systems. Laptops, he explained, have a different display architecture than desktops, with a more direct interface between the GPU and the LCD panel, generally based on standards like LVDS or eDP (embedded DisplayPort). Desktop monitors use other interfaces, like HDMI and DisplayPort, and typically have a scaler chip situated in the path between the GPU and the panel. As a result, a feature like variable refresh is nearly impossible to implement on a desktop monitor as things now stand.
That, Petersen explained, is why Nvidia decided to create its G-Sync module, which replaces the scaler ASIC with logic of Nvidia's own creation. To his knowledge, no scaler ASIC with variable refresh capability exists—and if it did, he said, "we would know." Nvidia's intent in building the G-Sync module was to enable this capability and thus to nudge the industry in the right direction.